Factors that limit maintenance of recombinant rumen bacterium in sheep rumen

Kobayashi, Yasuo; Yamamoto, Masanori

doi:10.1046/j.1344-3941.2002.00019.x

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…Kobayashi et al 10) inoculated recombinant Butyrivibrio fibrisolvens into the rumen of sheep, but its population in the rumen fell to undetectable levels within 7 days. They postulated that some antibacterial factors, such as bacteriocin, might exist in the rumen fluid and act as major inhibitors of survival 11) . More studies are required on the rumen microbial ecosystem to develop successful strategies for novel bacterial inoculation.…”

Section: Molecular Genetics For Ruminal Fibrolytic Systemsmentioning

confidence: 99%

Recent Topics in Rumen Microbiology with Particular Reference to Animal Production in Japan

Itabashi

2004

Microb. Environ.

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Microbes with which ruminants have established symbiotic relationships include bacteria, protozoa and fungi. Microbiological studies in Japan have emphasized the ecology of the ruminal system including the physiological and biochemical interrelationships between individual microbes. The difference in the distribution of various types of microbes in the rumen was studied first and the importance of the attachment of microbes to solid feed substrates was clarified. The existence of substrate-binding factors in bacteria has also been demonstrated. Many genes encoding fibrolytic enzymes have been cloned and characterized from ruminal microbes to improve the digestion of fiber. Some highly fibrolytic bacteria were produced and the survival of recombinant bacteria in the rumen was studied. The manipulation of ruminal bacteria has not been successful and is still at a challenging stage. Both microbial genetics and ecological approaches are needed to improve ruminant productivity through microbial manipulation. As for the study of microbial protein and amino acid metabolism, a particular emphasis was given to the role of ciliate protozoa. The synthesis of lysine from diaminopimelate by protozoa was demonstrated. The metabolic pathways for many kinds of amino acids were well studied, and it was shown that protozoa actively decompose feed protein and excrete amino acids as metabolic products. Therefore, protozoa tended to reduce the microbial amino acid flow to the intestine. A specific role for pipecolic acid in the physiology and behavior of the host animal was postulated. Protozoal function is still an important problem and deserves further research. Concerning the metabolism of carbohydrate, the reduction of ruminal methane production has been studied because methane is viewed as a pollutant greenhouse gas. Some possible methods of reducing methane production with the least adverse effect have been developed. In this review, some recent topics in ruminal microbiology are described.

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Section: Molecular Genetics For Ruminal Fibrolytic Systemsmentioning

confidence: 99%

Recent Topics in Rumen Microbiology with Particular Reference to Animal Production in Japan

Itabashi

2004

Microb. Environ.

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“…These new bacteria usually show poor survival or fail to become established in the animal gut. Previously, we examined factors that might inhibit the survival of genetically altered B.fibrisolvens in the rumen (Kobayashi et al, 2001;Kobayashi and Yamamoto, 2002). The success of inoculating sheep with our recombinant B. fibrisolvens was dissapointing, with ruminal density falling to undetectable levels within 7 days.…”

Section: Survival Of Newly Introduced Bacteriamentioning

confidence: 99%

Recent Advances in Gut Microbiology and Their Possible Contribution to Animal Health and Production - A Review -

Kobayashi¹,

Koike²,

Taguchi³

et al. 2004

Asian Australas. J. Anim. Sci

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Although gut microbial functions have been analyzed through cultivation of isolated microbes, molecular analysis without cultivation is becoming a popular approach in recent years. Gene cloning studies have partially revealed the mechanisms involved in fiber digestion of individual microbe. The molecular approach finally made it possible to analyze full genomes of the representative rumen cellulolytic bacteria Fibrobacter and Ruminococcus. The coming database may contain useful information such as regulation of gene expression relating to fiber digestion. Meanwhile, unculturable bacteria are still poorly characterized, even though they are main constituents of gut microbial ecosystem. The molecular analysis is essential to initiating the studies on these unculturable bacteria. The studies dealing with rumen and large intestine are revealing considerable complexity of the microbial ecosystems with many undescribed bacteria. These bacteria are being highlighted as possibly functional members contributing to feed digestion. Manipulation of gut bacteria and gut ecology for improving animal production is still at challenging stage. Bacteria newly introduced in the rumen, whether they are genetically modified or not, suffer from poor survival. In one of these attempts, Butyrivibrio fibrisolvens expressing a foreign dehalogenase was successfully established in sheep rumen to prevent fluoroacetate poisoning. This expands choice of forages in tropics, since many tropic plants are known to contain the toxic fluoroacetate. This example may promise the possible application of molecular breeding of gut bacteria to the host animals with significance in their health and nutrition. When inoculation strategies for such foreign bacteria are considered, it is obvious that we should have more detailed information of the gut microbial ecology.

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Recombinant Technologies to Improve Ruminant Production Systems: The Past, Present and Future

et al. 2020

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The use of recombinant technologies has been proposed as an alternative to improve livestock production systems for more than 25 years. However, its effects on animal health and performance have not been described. Thus, understanding the use of recombinant technology could help to improve public acceptance. The objective of this review is to describe the effects of recombinant technologies and proteins on the performance, health status, and rumen fermentation of meat and milk ruminants. The heterologous expression and purification of proteins mainly include eukaryotic and prokaryotic systems like Escherichia coli and Pichia pastoris. Recombinant hormones have been commercially available since 1992, their effects remarkably improving both the reproductive and productive performance of animals. More recently the use of recombinant antigens and immune cells have proven to be effective in increasing meat and milk production in ruminant production systems. Likewise, the use of recombinant vaccines could help to reduce drug resistance developed by parasites and improve animal health. Recombinant enzymes and probiotics could help to enhance rumen fermentation and animal efficiency. Likewise, the use of recombinant technologies has been extended to the food industry as a strategy to enhance the organoleptic properties of animal-food sources, reduce food waste and mitigate the environmental impact. Despite these promising results, many of these recombinant technologies are still highly experimental. Thus, the feasibility of these technologies should be carefully addressed before implementation. Alternatively, the use of transgenic animals and the development of genome editing technology has expanded the frontiers in science and research. However, their use and implementation depend on complex policies and regulations that are still under development.

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Factors that limit maintenance of recombinant rumen bacterium in sheep rumen

Cited by 3 publications

References 19 publications

Recent Topics in Rumen Microbiology with Particular Reference to Animal Production in Japan

Recent Topics in Rumen Microbiology with Particular Reference to Animal Production in Japan

Recent Advances in Gut Microbiology and Their Possible Contribution to Animal Health and Production - A Review -

Recombinant Technologies to Improve Ruminant Production Systems: The Past, Present and Future

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